1. Field of the Invention
The present general inventive concept relates to a color signal processing apparatus and method. More specifically, the present general inventive concept relates to a color signal processing apparatus and method capable of adaptively transforming a color gamut of a video being reproduced depending on an input video.
2. Description of the Related Art
Typically, a reproducing device, such as a monitor or a scanner, utilizes a color space or a color model that is suited for its own purpose. For example, a color video printing device works in a CMY color space, and a color cathode ray tube (CRT) monitor or a computer graphic device works in an RGB color space. A device processing hue, saturation and intensity works in an HSI color space. In addition, a CIE color space, in which any device can work with high accuracy, can be used to define device-independent colors. The CIE color space includes are CIE-XYZ, CIE L*a*b, and CIE L*u*v color spaces.
A color reproducing device may use various colors according to the color space being worked in. The color reproducing device typically uses three primary colors. In particular, the RGB color space, in which the color CRT monitor and the color graphic device work, uses three primary colors including red, green, and blue. The CMY color space, in which the color video printing device works, uses three secondary colors including cyan, magenta, and yellow.
The color reproducing device may employ a specific color gamut as well as the color space. While the color space defines colors (i.e., a relationship between colors) the color gamut represents a range of possible colors that can be reproduced by mixing the colors. Accordingly, the color gamut, which is the color range that is reproducible by a color reproducing device, depends on the primary colors used by the color reproducing device. FIG. 1 is a diagram illustrating a color gamut reproducible by a conventional color reproducing device. As illustrated in FIG. 1, inside of a triangle GAMUT1, which is formed by lines between primary colors P1, P2, and P3 used by the conventional color reproducing device in a CIE-XYZ color space, represents the color range that is reproducible by the conventional color reproducing device. If the conventional color reproducing device uses the primary colors P1, P2, and P3, the inside of the triangle GAMUT1 indicates the corresponding color range or the color gamut. If the conventional color reproducing device uses the primary colors P1′, P2′, and P3′, the inside of a triangle GAMUT2 indicates the corresponding color range.
However, when reproducing an input video that complies with a general broadcast standard or a color signal standard, the conventional color reproducing device uses its own specified primary colors. Accordingly, the video is reproduced having a limited brightness and a limited contrast even when a distribution of colors of the input video is limited to a part of the entire color gamut.